FIELD OF THE INVENTION
This invention relates generally to methods of integrated circuit assembly and packaging techniques, and more particularly to a batch processing method and apparatus for solder sealing lids on integrated circuits. Currently, the packaging processing is the most inefficient phase of integrated circuit manufacturing. Because the packaging process can be labor intensive, the packaging costs can easily exceed the costs of the integrated circuit. Also, packaging and assembly are critical steps in the integrated circuit fabrication process which affects the yield and reliability.
The packaging may be accomplished by utilizing soldered seals which may be produced by a number of well-known methods. The package assembly and lid are placed in a mold with solder between them, such that when heated the solder free-flows around the lid to form a hermetic seal. The packaging lid assembly is held in alignment by means of spring clips or weights which force together the surfaces to be soldered.
The existing methods of sealing ceramic chip carrier assemblies are slow, bulky, and unreliable. They do not ensure lid-to-carrier orientation throughout the oven sealing process. It is difficult to provide adequate horizontal leveling of the assemblies, resulting in solder-flow buildup in one area. The solder preform can be damaged or dislodged from the lids during the lid alignment or clamping operation. But more importantly, these techniques are labor intensive which adds to the overall costs of the manufacturing process.